[rules_go] show x archive isn't stable to package interface

tests/core/go_library/reproducible_x/BUILD.bazel

@@ -0,0 +1,22 @@
+load("//go:def.bzl", "go_binary", "go_library")
+
+go_library(
+    name = "calculator",
+    srcs = [
+        "calculator.go",
+    ],
+    importpath = "calculator",
+)
+
+go_binary(
+    name = "main",
+    srcs = [
+        "main.go",
+    ],
+    deps = [":calculator"],
+)
+
+sh_binary(
+    name = "show_not_reproducible",
+    srcs = ["show_not_reproducible.sh"],
+)

tests/core/go_library/reproducible_x/calculator.go

@@ -0,0 +1,39 @@
+package calculator
+
+import (
+	"errors"
+)
+
+// Calculator interface defines the basic operations
+type Calculator interface {
+	Add(a, b float64) float64
+	Subtract(a, b float64) float64
+	Multiply(a, b float64) float64
+	Divide(a, b float64) (float64, error)
+}
+
+// SimpleCalculator struct that implements the Calculator interface
+type SimpleCalculator struct{}
+
+// Add method
+func (c SimpleCalculator) Add(a, b float64) float64 {
+	return a + b
+}
+
+// Subtract method
+func (c SimpleCalculator) Subtract(a, b float64) float64 {
+	return a - b
+}
+
+// Multiply method
+func (c SimpleCalculator) Multiply(a, b float64) float64 {
+	return a * b
+}
+
+// Divide method (with error handling for division by zero)
+func (c SimpleCalculator) Divide(a, b float64) (float64, error) {
+	if b == 0 {
+		return 0, errors.New("division by zero is not allowed")
+	}
+	return a / b, nil
+}

tests/core/go_library/reproducible_x/main.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"calculator"
+	"fmt"
+)
+
+func main() {
+	// Create an instance of SimpleCalculator
+	calculator := calculator.SimpleCalculator{}
+
+	// Perform some operations
+	fmt.Println("Add: 5 + 3 =", calculator.Add(5, 3))
+	fmt.Println("Subtract: 5 - 3 =", calculator.Subtract(5, 3))
+	fmt.Println("Multiply: 5 * 3 =", calculator.Multiply(5, 3))
+
+	result, err := calculator.Divide(5, 0)
+	if err != nil {
+		fmt.Println("Error:", err)
+	} else {
+		fmt.Println("Divide: 5 / 3 =", result)
+	}
+
+	result, err = calculator.Divide(5, 3)
+	if err != nil {
+		fmt.Println("Error:", err)
+	} else {
+		fmt.Println("Divide: 5 / 3 =", result)
+	}
+}

tests/core/go_library/reproducible_x/show_not_reproducible.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd "${BUILD_WORKSPACE_DIRECTORY}"
+BAZEL_BIN="$(bazel info bazel-bin)"
+
+tmp_output="$(mktemp -d)"
+
+function build_and_show_hash() {
+  echo "Building..."
+  bazel build //tests/core/go_library/reproducible_x:calculator
+  printf "\n\n\n"
+  echo "Taking hash of .x file"
+  cp "$BAZEL_BIN/tests/core/go_library/reproducible_x/calculator.x" "$tmp_output/calculator_$1.x"
+  shasum -a 256 "$BAZEL_BIN/tests/core/go_library/reproducible_x/calculator.x" > "$tmp_output/calculator_$1.x.sha256"
+  printf "\n\n\n"
+}
+
+build_and_show_hash "original"
+
+echo "Changing the source code"
+sed -i 's/division by zero is not allowed/division by zero is not allowed - modified/g' tests/core/go_library/reproducible_x/calculator.go
+
+build_and_show_hash "modified"
+
+echo "Comparing the hashes..."
+if diff "$tmp_output/calculator_original.x.sha256" "$tmp_output/calculator_modified.x.sha256"; then
+  echo "Hashes are the same. Output is reproducible"
+else
+  echo
+  echo
+  echo "Hashes are different"
+  echo "Export archives are saved in $tmp_output"
+  echo
+  ls -l "$tmp_output"
+  exit 1
+fi